Elevators typically include a car that moves vertically through a hoistway between different levels of a building. At each level or landing, a set of hoistway doors are arranged to close off the hoistway when the elevator car is not at that landing. The hoistway doors open with doors on the car to allow access to or from the elevator car when it is at the landing. It is necessary to have the hoistway doors coupled appropriately with the car doors to open or close them.
Conventional arrangements include a door interlock that typically integrates several functions into a single device. The interlock locks the hoistway doors, senses that the hoistway doors are locked and couples the hoistway doors to the car doors for opening purposes. While such integration of multiple functions provides lower material costs, there are significant design challenges presented by conventional arrangements. For example, the locking and sensing functions must be precise to satisfy codes. The coupling function, on the other hand, requires a significant amount of tolerance to accommodate variations in the position of the car doors relative to the hoistway doors. While these functions are typically integrated into a single device, their design implications are usually competing with each other.
Conventional door couplers include a vane on the car door and a pair of rollers on a hoistway door. The vane must be received between the rollers so that the hoistway door moves with the car door in two opposing directions (i.e., opening and closing). Common problems associated with such conventional arrangements are that the alignment between the car door vane and the hoistway door rollers must be precisely controlled. This introduces labor and expense during the installation process. Further, any future misalignment results in maintenance requests or call backs.
Additionally, with conventional arrangements debris build up on the door track and static pressure from the stack effect tend to impede the hoistway doors from fully closing. Moreover, with conventional designs, separately driving the hoistway doors closed causes delays in the door opening and closing times, which can appear to be an inconvenience to passengers.
It is desirable to have hoistway doors driven completely closed by the car doors (to avoid call back and maintenance problems) while at the same time addressing the aforementioned issues. There have been proposals to use electromagnetic elevator door coupler components. One such example is shown in the published application WO 2006/009536. Even with such advances, those skilled in the art are always striving to make improvements.